Infectious Canine Hepatitis

Canine viral hepatitis is a disease of dogs and does not affect humans. Fortunately the illness is far less common nowadays due to effective vaccination. However, this highly contagious and sometimes fatal disease is still seen occasionally in practice, especially in unvaccinated puppie

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  • Canine viral hepatitis (formerly called Rubarth’s disease) is caused by a virus, Canine Adenovirus Type 1 (CAV-1). In Europe, it affects primarily dogs and foxes.

    Dogs are infected via the mouth, throat and tonsils, before spreading and affecting other organs, especially the liver. The virus is usually shed in urine, faeces or saliva of infected dogs. It has been shown that recovered animals may shed virus in their urine for up to one year.

    The virus is resistant to many disinfectants, and can persist in the environment for months. Dogs are most commonly infected indirectly by virus left surviving in the environment rather than direct ‘dog to dog’ contact. In a kennel situation, spread can be rapid.

  • Symptoms can vary from very mild to sudden death.

    Hyperacute form: Puppies less than 3 weeks may show sudden abdominal pain, with death occurring within a few hours. This form is rarely seen nowadays.

    Acute form (classic disease): Early cases are often characterised by a marked lethargy. On examination, dogs have a high temperature, inflammation of the tonsils (tonsillitis) and enlarged lymph glands below the jaw. As acute tonsillitis is not common in dogs, its presence may be suggestive of infection. Vomiting and/or diarrhoea with inappetence usually then develops. Bright light may be painful for some dogs.

    The liver becomes painful and enlarged on palpation. Jaundice and bleeding from the gums may develop as the liver fails. At this stage, the mucous membranes become pale or jaundiced. A tucked up appearance due to the pain is common. About 20% of cases die and although those that survive the acute stage recover, it may take many weeks to regain condition.

    Mild form: A few dogs only develop a slight fever with enlarged lymph glands. Diarrhoea may also be seen.

    Variants: The clinical picture is much less varied than for distemper. However, convulsions very occasionally occur which might confuse the diagnosis with distemper. The surface of the eye may develop a milky blue appearance called ‘blue eye’ after recovery from the disease.

  • The veterinary surgeon may be able to make a presumptive diagnosis based on clinical signs in some cases. However, this is more difficult in the mild form as the symptoms are so vague.

    If further diagnostic tests are required the virus may be detected in a commercial laboratory, following sampling of the liver or an enlarged lymph node. Additionally the liver shows characteristic changes under the microscope if a post-mortem examination is performed.

  • Canine Adenovirus Type-1 cannot be treated specifically, and thus is limited to supporting the dog during the illness.

    Treatment may therefore include:

    • Medication to control symptoms, such as diarrhoea, vomiting, liver failure and blood clotting disorders.
    • Special diet to support liver function.
    • Anti-inflammatories.
    • Antibiotic treatment may be used to control any secondary bacterial infections.
    • Strict biosecurity precautions taken should be taken during illness.
    • Implementation of an exercise plan as severe setbacks may occur after excessive exercise even after apparent recovery.
  • Prevention is by vaccination. The canine viral hepatitis component is included in the primary vaccination course given to puppies, and often in routine annual boosters. Many vaccines use the CAV-2 strain rather than the CAV-1 (viral hepatitis) strain to protect against viral hepatitis, as this also provides cross-protection for some forms of kennel cough and is less likely to cause “Blue Eye” (oedema of the surface of the eye).

    Based on your pet’s specific situation, your veterinary surgeon will chose a protocol to best meet your pet’s needs.

    An up-to-date vaccination is usually obligatory before going to dog shows and many kennels.